The present invention relates to an apparatus for forming metallic binding bands which are to bind members such as gas hoses, etc.
Conventionally, a binding band is used when, for example, a gas hose is connected to a pipe. The binding band 1 (see FIG. 8) has a binding section 2, whose both ends are overlapped and fixed to form a ring, and a lever 4, which is overlapped and fixed on the overlapped section 3. And the binding band 1 further has a retaining piece for fixing the lever 4 on the binding section 2 after the lever 4 has been moved to its binding position. The binding band 1 bound is shown in FIG. 10.
The binding band is made by steps of cutting band-like material with a prescribed length to form the binding section 2, overlapping and fixing both ends of the binding section 2 to form the overlapped section 3, and overlapping and welding the one end of the lever 4 onto the overlapped section 3, so that the binding section 2 assumes a flattened ring shape (see FIG. 9). Therefore, a further step of forming the binding section 2 into a true circle shape is required.
To satisfy this requirement, a forming apparatus has been disclosed in Japanese Provisional Publication (KOKAI) No. 63-126631 (see FIG. 11). This apparatus has a pair of forming pieces 8 and 9, whose outer circumferential faces are arc-shaped and which are located in the loop section of the binding section and also has clipping members 6 and 7 for clipping the lever 4. The forming pieces 8 and 9 are mutually moved away in order to expand the binding section into a circle-like form.
In the conventional forming apparatus, however, the loop section of the binding section is not formed into a true circle because the forming pieces, whose shapes are the same, are moved in the same manner to expand the loop section despite that the shape of the ends of the binding section are different from each other as shown in FIG. 8.
Namely, in the overlapped section 3 of the binding band 1, the lever 4 is bent in the tangential direction of the loop section 2A of the binding section 2 to have the lever face up. With this structure, the overlapped section 3 has a U shaped bend. If the forming pieces 8 and 9, whose shapes are the same, are moved in the same manner, the parts of the loop section on each side of the overlapped section are transformed into different shapes from each other, so that the binding band 1 will be inferior.
Note that the reason why the lever 4 is faced up and bent in the tangential direction with respect to the loop section 2A is to increase the reducing the diameter of the loop section 2A when the lever 4 is turned.